Feature:1. Mounted on the outside of the helmet, compared with the built-in type, the internal earphone is thinner, does not squeeze the ear, and is more comfortable;2. It contains a larger capacity battery up to 450mAh the built-in type is about 250mAh, which makes the standby time and working time of the whole machine longer;3. Fix the Interphone with screws and bayonet, which makes the main unit installation tighter and high-speed riding is not easy to fall off;4. Use high-power audio amplifier to make the audio volume range larger, and it will not affect music playback and telephone answering in the noise environment of high-speed riding;5. Use Premium quality amp chip to restore Bluetooth audio with high sound quality;Specification:BT chipset Version: 4.1EDR CSR8635BT profile: A2DP and ACRCPBattery Capacity: 450mAhCharging Voltage/Current: DV 5V/190mAFrequency: 2.4GHzAmplifier: HT4832SQWorking duration: 10 hoursMobile phone distance: 50 meter Package List:1 x Bluetooth Headset Interphone1 x User Manual1 x Mic1 x Bracket2 x HookLoops2 x Screws1 x Charging Cable